Automatic braking device for hydraulic pressure chair

ABSTRACT

This invention provides an automatic braking device for vertically adjustable hydraulic chairs. The invention is incorporated within the hydraulics and instantly stops and locks the chair seat at any height, without the requirement of external locking means.

United 1 51111638 Patent 1 [111 3,777,617 Okiyama 1 Dec. 11, 1973 [54] AUTOMATIC BRAKING DEVICE FOR 2,889,895 6/1959 Snow 92/28 HYDRAULIC PRESSURE CHAIR 3,508,794 4/1970 Engle. 91/44 2,341,465 2/1944 Monnot 188/67 [76] Inventor: Masaharu Okiyama, 3131-1 Oaza 3,400,73 9/19 8 Murich etal, 188/67 Anamushi Kashiba-cho, 3,064,464 11/1962 Black et al........ 91/44 Kitakatsuragi-gun, Nara, Japan 3,230,714 l/l966 Redfield 91/44 [22] Filed: Nov. 16, 1971 21 APPL 199,27 Primary Examiner-Martin P. Schwadron Assistant Examiner-A. M. Zupcic Attorney-Arnold Robinson [30] Foreign Application Priority Data Dec. 14, 1970 Japan 45/112209 [52] US. Cl 91/44, 92/28, 188/67, [57] ABSTRACT 248/410, 297/347 [51] Int. Cl. F15b 15/26 This invention provides an automatic braking device Field Of Search for vertically adjustable hydraulic chairs. The inven- 60/5 7/ 7 tion is incorporated within the hydraulics and instantly 92/25, 27, 28; stops and locks the chair seat at any height, without the requirement of external locking means. [56] References Cited UNITED STATES PATENTS 2,139,185 12/1938 Engel 91/44 5 Claims, 4 Drawing Figures PAIENTED ml 1 SHED 1 BF 3 H27 wi AUTOMATIC BRAKING DEVICE FOR HYDRAULIC PRESSURE CHAIR This invention relates to an automatic braking device to be incorporated in a vertically adjustable hydraulic chair, which is commonly used at barber shops, beauty parlors, hospitals, offices, design rooms, schools, et cetera. More specifically, the invention is concerned with improvements upon a vertically adjustable hydraulic chair by providing an automatic braking device'operable in association with an adjusting hydraulic. means, whereby the chair seat is locked at any optional height in the process of adjusting movement, without use of any extra locking means.

In known chairs utilizing a hydraulic method, a pedal pump is employed for effecting hydraulic pressure. However, the greatest disadvantage of this type is that the adjustable heights are extremely limited because of the incapability of stopping the chair seat instantly and securely in the process of its movement. Therefore, the chair seat is locked only when it reaches its terminal position or any other predetermined position. Another disadvantage is that the pedal pump calls for ones pedal labor while he is attending to his work. In addition, the pedal takes the form of a lever tending to extend underneath the seat, which is likely to stand in ones way and to spoil the appearance of the chair.

Another proposal is a hydraulic pressure chair of the type in which each performance of raising, lowering, stopping, and locking the chair seat is operated by different electric equipment with the use of many expensive elements and devices, such as solenoid valves, which results in increased cost, complexity and size.

Therefore, the primary object of the present invention is to provide an improved braking device adapted for incorporation in vertically adjustable hydraulic chairs. Another object of the invention is to provide an automatical braking device capable of eliminating the need for manual and pedal labor. Still another object of the invention is to provide an automatical braking device whereby the chair seat is instantly and securely stopped at any optional height in the process of its adjusting movement.

According to the present invention, a chair seat is raised and lowered under the action of hydraulic pressure, in association with which braking is optionally applied to control its movement, thereby securing the setting of the chair seat at the optimum height for the sitter.

The invention will be more particularly described by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a sectional view of a device according to the present invention. I a

FIG. 2 is a schematic side view of the main part of the device according to the invention.

FIG. 3 is a schematic plan view of the part illustrated in FIG. 2.

FIG. 4 is a schematic front view of the part illustrated in FIG. 2.

Referring to FIG. 1, a plunger 1 is slidably received through O-rings 24 in a cylindrical plunger chamber 6 of a base column 5, which includes an oil sump 4 in its upper part and a cylindrical piston rod chamber 7, the two cylindrical chambers being arranged in parallel with each other. The plunger 1 passes through a cover 3 and is connected to a seat plate 23. A piston rod 2 housed in the chamber 7 has a coil spring (B) wound around its outside surface, which. is located between flanges 16., and 17. The flange 17 is adjustably screwed in the cover 3 to control the strength of the spring (B). As a result, spring (B) normally urges the piston rod 2 downwards.

The portion of the plunger 1 extending above the cover 3 is encircled by a brake bracelet 9 of U-shape, having two legs 9' and 9", and a gap 8 therebetween capable of allowing the legs to open and close. Either of the legs 9, 9" is fastened to the cover 3by means of a bolt 10. Below the brake bracelet 9 is provided a framework 12 having a brake shoe 11. Preferably, the brake shoe ll slants openly in relation to the brake bracelet 9, as shown in FIG. 4. The framework 12 is swingably supported with its shafts 13 in receipt of bearings 14, which are attached to the cover 3. One of the frames is pivotably connected to the piston rod 2 by means of a pin 15, so that the framework 12 can swing around the shafts 13 like a seesaw as the piston rod 2 moves up and down.

The operation of the device of the present will be explained as follows:

Hydraulic pressure is effected by an electrically driven pump (not shown) mounted in place under the base column 5, raising the piston rod 2 against the force of the coil spring (B), prior to the movement of the plunger 1, with a check valve 18 plugging the passageway 20 of liquid communicating with the plunger chamber 6. In conjunction with the rising of the piston rod 2, the unfastened side of the framework 12 lowers, bringing the brake shoe 11 out of contact with the legs 9', 9" of the brake bracelet, and thereby allowing the plunger 1 to move. When the chair seat reaches the po sition as required, the pump is de-energized to stop the liquid flow in the piston rod chamber. As the liquid flow loses its pressure, the coil spring (B) returns to its original condition, assisted by the reverse flow of the liquid. The piston rod 2 is lowered under the urge of the returning spring (B), whereby the brake shoe is placed into contact with the legs 9', 9" of the brake bracelet, putting a brake upon the plunger 1. As the legs 9' 9" of the bracelet are engaged by the brake shoe 11, they are closed, tightening around the plunger 1 and locking it in place. When the chair seat is to be lowered, the pump is energized to raise the piston rod 2 to the extent that the brake shoe 11 comes out of contact with the brake bracelet 9, allowing the seat to descend by gravity. The downward movement of the seat is continued as long as the pump is energized to disengage the brake shoe 11 from the brake bracelet 9. When the pump is de-energized, the liquid flow comes to a standstill, letting the coil spring (B) return to its original position, with the brake shoe being placed into contact with the brake bracelet 9.

In the preferred embodiment, the brake bracelet is made of cast iron, and normally loosely encircles the plunger 1 so as to allow it to move up and down, As de scribed above, when the brake bracelet 9 comes into engagement with the brake shoe 11, its legs 9, 9" are closed, tightening around the plunger 1, so that the plunger is braked from further movement. When the brake bracelet 9 is set free from the brake shoe 11, the legs 9', 9" are opened, permitting the plunger to move up and down. It is necessary that the valve spring 19 of the check valve 18 be of such a nature as to return to its original condition more quickly than the coil spring invention (B), thereby allowing a liquid flow into the plunger chamber 6 by way of passageway 20. The liquid is delivered from an inlet port 21 by means of an oil pump (not shown). The liquid flow is controlled by a conventional solenoid valve 22. The reference numeral 26 is a cover totally housing the operating section of the device, and the reference numeral 25 is a base plate for supporting the operating section.

It is not intended that the invention be limited to use in hydraulic chairs, but may be incorporated into any hydraulic lift system using a plunger connected to a load.

It will be understood that it is to cover all changes and modifications of the preferred embodiments of the invention herein chosen for the purpose of illustration which do not constitute departure from the spirit and scope of the invention.

What I claim is:

1. An automatic braking device for a hydraulic lift system comprising:

a. a plunger having a first axis along its length connected to a load and moveable under hydraulic pressure along said first axis;

b. a U-shaped brake bracelet having two legs disposed in a common plane which is perpendicular to said first axis and a gap between said legs, said legs and said gap encircling said plunger, said legs being operative to move in said plane to close and open said gap;

c. framework and pivot means for pivotally mounting said framework means about a second axis which is perpendicular to said first axis, said framework means being pivotally moveable;

d. a brake shoe disposed on said framework means which is operative to move said legs to close and open said gap in response to said pivoting movement of said framework means; and

e. means to pivotally move said framework about said second axis.

2. An automatic braking device as claimed in claim 1 wherein said means to pivotally move said framework means comprises a piston rod moveable in a direction parallel to said plunger and a coil spring operative to bias said piston rod in a first position.

3. An automatic braking device as claimed in claim 2 further comprising a first chamber for housing said plunger and a second chamber for housing said piston rod, said chambers being in communication with each other by means of at least one passageway.

4. An automatic braking device as claimed in claim 3 further comprising valve means for controlling hydraulic flow into said chambers, said valve means comprising a spring operative to react more quickly than said coil spring to permit hydraulic flow into said first chamber after movement of said piston rod is stopped.

5. An automatic braking device as claimed in claim 1 wherein said brake bracelet further comprises a face and wherein said brake shoe slants in relation to said face, said slanting of said brake shoe being operative to move said brake bracelet legs to close and open said gap upon pivoting of said brake bracelet. 

1. An automatic braking device for a hydraulic lift system comprising: a. a plunger having a first axis along its length connected to a load and moveable under hydraulic pressure along said first axis; b. a U-shaped brake bracelet having two legs disposed in a common plane which is perpendicular to said first axis and a gap between said legs, said legs and said gap encircling said plunger, said legs being operative to move in said plane to close and open said gap; c. framework and pivot means for pivotally mounting said framework means about a second axis which is perpendicular to said first axis, said framework means being pivotally moveable; d. a brake shoe disposed on said framework means which is operative to move said legs to close and open said gap in response to said pivoting movement of said framework means; and e. means to pivotally move said framework about said second axis.
 2. An automatic braking device as claimed in claim 1 wherein said means to pivotally move said framework means comprises a piston rod moveable in a direction parallel to said plunger and a coil spring operative to bias said piston rod in a first position.
 3. An automatic braking device as claimed in claim 2 further comprising a first chamber for housing said plunger and a second chamber for housing said piston rod, said chambers being in communication with each other by means of at least one passageway.
 4. An automatic braking device as claimed in claim 3 further comprising valve means for controlling hydraulic flow into said chambers, said valve means comprising a spring operative to react more quickly than said coil spring to permit hydraulic flow into said first chamber after movement of said piston rod is stopped.
 5. An automatic braking device as claimed in claim 1 wherein said brake bracelet further comprises a face and wherein said brake shoe slants in relation to said face, said slanting of said brake shoe being operative to move said brake bracelet legs to close and open said gap upon pivoting of said brake bracelet. 